One of the long term objectives of this project is to provide physical parameters that give quantitative measures regarding the quality of lenses. These pertain both to normal and cataractous human lenses. A number of light scattering and dielectric parameters will be obtained on whole lenses and they will be correlated with slit lamp observation taken prior to the removal of the cataract and acuity tests taken pre- and post-operatively as well as with the classification of the cataracts. A second objective of the project is to analyze the physical processes such as syneresis, aggregation, cytoskeletal body disorientations, etc. that lead to cataract formation. Great emphasis is put to study the precataractous conditions in order to see if any of these processes are reversible and, if so, at what stage of cataractogenesis such reversal can still be accomplished. In quest of this aim, differential scanning calorimetry together with thermogravimetric analysis will be used to monitor the change in bound/free water ratio, a measure of syneresis. Difference spectra in the near infra-red on lens sections will be studied to support the thermal analysis. We also use light scattering and other optical measurements on microdomains of cataractous lenses to describe the structural features and the changes in them that contribute to cataractogenesis. We also will investigate the vitreous, its structure or the changes in it as they affect the lenses, especially the posterior subcapsular cataract formation prevalent in diabetics. Finally, the distribution of fluorophores within human lenses will be studied and the relationship of such distribution to cataractogenesis.